Combined type-writing and computing machine.



H. HANSON. COMBINED TYPE WRITING ANI) COMPUTING MACHINE.

t q APPUC-ION FLED MAY Il' |911- y l ,275, 8 T23 Patented Sept. 10,1918. v 15 SHEETS-SHEET II Il l me IIJI IIIIIIII II IIIIIIIIIIJIIIIIIIIIIDUIIIJDIIIIBIIIIIIIIIIIIIIIIIIIIIIIIIIBIIII Imam; 1O

WITNESSEM I 5MM/U1 H. HANSON.

COMBINED TYPE WRITING AND COMPUTING MACHINE.

APPLlcATIoN HLED MAY11. 1911.

Patented Sept. 10, 1918.

l5 SHEETS-SHEET 2.

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l H. HA-NsoN. COMBINED TYPE WRITING AND COMPUTING MACHINE.

APPLICATION FILED MAY I1, |9II.

1,278,812, Patented sept. 10,1918.

I5 SHEETS-SHEET 3.

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H. HANSON.

COMBINED TYPE WRITING AND COMPUTING MACHINE.

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COMBINED TYPE wmm AND COMPUTING 'MAcHlNL APPLilCATiON FILED MAY 1I. 191l. 1,278,81 2. Patented sept. 10,1918.

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COMBINED TYPE WRITING AND COMPUTING-MACHINE.

APPLICATION FILED MAYII, T911.

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H. HANSON.

COMBINED TYPE WRITING AND COMPUTING MACHINE.

APPLICATION FIIEED MAY II. I9II.

1,278,812. EaIenIed sept. 10,1918.

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WITNESSESI INVENTURT BY ATTORNEM H. HANSGN.

COMBINED TYPE WRITING AND COMPUTING MACHINE.

APPLICATION FILED IIAYII, 191|.

1,278,812. Patented sept. 10,1918..

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FIGJQ.

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H. HANSON.

COMBINED VTYPE WRITING AND COMPUTING MACHINE.

APPLICATION FILED MAYII,-I9|1.

1 ,278,8 1 2'. Patented Sept. 10, 1918.

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H. HANSON.

COMBINED TYPE WRITING AND COMPUTING MACHINE.

APPLICATION F|LED MAY HI 191i. 1 ,278,812. Patented Sept. 10, 1918,

15 SHEETS-SHEET l0.

F|GI.22

WITNESSESI INVENTOR:

ATTORNEY.

H.HANS0N. COMBINED TYPE WRITING AND IOMPUTING MACHINE.

Patented Sept. 10, v1918.

APPLICATION FILED MAY Il. IBI I. 1,278,812@

15 SHEETSSHEET II- nw n; @EDGE I NVENTOR! /m www TTORN/ .UNQI

wlT'NEssEs:

H. HANSON. COMBINED TYPE wmT|NG AND COMPUTING MAcHlNE.

APPLICATION FILED MAY Il. |911.

' Patented Sept.Y 10, 1918.

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H.-HANSON.

COMBINED TYPE WRITING AND COMPUTING MACHINE.

MfPLIcATIoN FILED MAY Il. 19H.

1,278,812. l Patented sept. 10,1918.

15 SHEETS-SHEET I3.

WIITNE-SSES: INVENTOR:

H.HANSOM COMBINED TYPE WRITING ANC COMPUTING MACHINE APPLICATION FILEDMAY II, I9II.

' 1 ,278,8 1 2 Patented Sept. 10, 1918..

I5 SHEETS-SHEET I4- INVENTUM ATTORNEY H. HANSON.

COMBINED YFE WRITING AND COMPUTING MACHINE.

APPLlcATloN man MMU. 1911.

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' UNITED STATES PATENT OFFICE.

I-IANS HANSON, OF HARTFORD, CONNECTICUT, ASSIGNOR, BY MESNE ASSIGNMENTS,

T0 UNDERWOOD COMPUTING MACHINE COMPANY, OF NEW YORK, N. Y., A CORPO-RATION OF NEW YORK.

COMBINED TYPE-WRITING AND COMPUTING MACHINE.

Application led May 11, 1911.

To all whom t may concern:

Be it known that I, HANs Hanson, a citizen of the United States,residing` in Hartford,` in the county of Hartford and State ofConnecticut, have invented certain new and useful Improvements inCombined Type-lVriting and Computing Machines, of which the following isa specification.

This invention relates to addingI or computing,` machines, particularlyof that type in which numeral keys are caused to set pins or deviceswhich determine the rotation of the number wheels or devices; the latterbeing actuated by a general operator or prime n'iover after theoperation of the numeral keys.

The principal object of the invention is to provide practicable meansfor performingsubtraction in machines of this general character. Thenumber wheels in such machines are usually constructed to turn in onlyone direction, and by means 0f my invention it is practicable to performsubtraction by advancing the wheels in the same direction` In thepreferred form of the invention, I provide a subtraction key, which ispressed by the operator, whenever he desires to adjust the machine sothat it will perform subtraction instead of addition. lVhen theinvention is carried out in the manner illustrated in the drawings, theoperation of said subtraction key will setthe 9 pins for all the numberwheels, thus providing that every wheel shall be turned at least ninesteps at the subsequent movement of the general operator, unless one ormore of the set 9 pins are restored and other pins set instead thereof.The mechanism controlled by the numeral keys is affected by saidsubtraction key in such a manner that any numeral key, when setting itspin, auton1atically restores the previously set 9 pin. By reason of anadditional function of the Snbtracti on key, the numeral keys are causedat the subtraction operation to set complementary pins, or at least eachkey is caused to set a pin whose value'is one less than the complementof the operated key. For instance, if key 2 is depressed' it sets thepin 7, which is one less than the comple Specification of LettersPatent.

Patented Sept. 10, 1918.

Serial No. 626,550.

ment of 2. Hence, at the subsequent operation of the general operator,the number wheels are advanced each to an extent which is one less thanthe complement of the operated key; while such wheels as are notaffected by the keys, are caused to advance nine steps. This occurs,according to the preferred form of the invention, during the initialstroke of the general operator. Another function of the general operator(when subtracting) is to advance the units wheel one eXtra step; and itwill be readily seen that this may bring into action the tens-carryingmechanism. And the movementof the tens-carrying train, which prefeerably takes place during the return stroke of the general operator, mayproceed along the Whole gang of number wheels, so that at the completionof the operation, certain of said wheels will show at the sight holenumbers which are the full complements of the operated keys, whileothers of said wheels (having` merely performed a complete revolution)will show the saine numbers as before the subtraction operation. Furtherparticulars and illustrations of the operation of the number wheels willbe given hereinafter.

Heretofore it has been suggested to perform subtraction by adding` thecomplement of the subtrahend, but the difficulty has been encounteredthat such addition of complement involves the carrying` of 107 over tothe wheel of next higher denomination, so that for instance if it wereattempted to take at from 19 the result would show as 25. Thisdiiiicult-y is overcome by my invention, since the carrying' of l0 tothe neXt higher wheel (which has already been advanced idly 9 steps)merely serves to complete an entire revolution of the latter, so that itreads the same as before the subtraction operation. Thus I automaticallycancel the effect of spurious tens-carry ing that occurs whensubtracting by means of the addition of complements.

At the completion of the subtraction operation, the machine ispreferably restored automatically to condition to perform addition.

?rovisen is also und@ whereby, after the subtraction key has beenoperated, the usual error key may be employed to restore the machine toycondition to perform addition, as well ast restore' any pins'that may'have been set.

:Provision is also preferably made, whereby the'types'are'caused tostrike through a ribbon olf different color Vwliena number is beingsubtracted.

The invention is illustrated in connection with the well known Underwoodcombined gpewriting and yadding machine of ythe anson typeillustrated'in Patents 816,319

and 905,421-2, and in other pending appli' Y combinedtypewritingandadding machine of the Hanson Jtype, embodying 'the presentimprovements.l

Fig. Q'i's" a side elevation of the same. Fig. 3 is a rear elevation ofthe machine. Fig. 4C is a side elevation of devices employe'd for givingthe units'wheel an VeXtra advance of one step atV the subtractionoperation 'g the parts being shown at the end of the initial strokeofthe general operator.

' Fig. 5 is av sectionalelevation from front to "rear of the 'principalportions of the wheel-'operating mechanism.

Fig. Gis a view taken at'tlic opposite side of the machine fromV Fig. 5,and showing a pin on one of the wheel-controlling "rack bars as havingbeen set, and as now' being engaged by the general' operator todriv-e'its wheel' forward. This shows the general operator at thecompletion of its initial erforward Vstroke toward the right.

"Figf isV a'sectional' elevation on a larger scale ofthe devices seen inthe rear portion of Figf; the 9 pins having been set by thesubtractionkey, as well'as the pin wherebyY the uiiit's wheel is 'givenan eXtra advance 'of on'e step.

lFig. 8 is a plan of the wheel-rotating rack bars, 'andthe nest of pinscarried thereon.

Fig; 9 is a bottom view vof'a plate connectedtothe'error key' and alsoto the general operator, whereby is"I effectedl the restoration ofanypins that may 'have been set.

Fig. 10 is a sectional elevation taken from front to rear,` showingthe'relation between the pin-setting bars, and one of' thevkey-controlled shaft-carrying arms 'which coperates with said bars 5 theShaftbelg ShQWIl'i shifted endwise to subtracting position; an arm onthe rear end of said shaft being in the position :to operate a bar thatrestores any `previously set 9 pin.

Fig. 11 is a sectional elevation, and Fig. 12 is a part-sectional plan,Ato show details of thel settable Vpins, andfmounts therefor.

Fig. 13'sh`ows ya ball `cliitcl'i usually employed between'a pinion,which is connected tothe reciprocatory general operator, and

a shaft whereon is mounted a set of segments forming .part of atens-carrying train;

1 1 is a plan and Fig. 15 an elevation of one of the wheel-operatingrack bars.

Fig. 16 is a frontelevatien of lthe forward portion of the errorlkeymechanism. i l 'r Fig. 17 is a side elevation of a VtypeoperatingnumeralA key. l ""Fig. 18 is a rear elevation of the linkages lformingpart Vof the mechanism whichselects the frack bars to operate the numberwheels. Vl`Figl 19:)is a general plan of the computing mechanism'. l

YFig-'2.0 is a Plan 0f a nest 0f Pin-Setting linkages, and shows crossedrows ofkey-controlled rack-arms shiftable from one vset of linkages :to`another iny order to' effect subtraction. l i

Fi'g'jQl is a front elevation of the devices seen'at Fig. 20, showingalso the set-table pins and the pin-restoring plate.

Figl'22 is a rear perspective view of the pin-setting linkages,pin-carrying rack bars, ctc."

Fig. 23 is a rear elevation of a linkage that restores any set 9 pinwhenever any numeral'key is operated the subtraction op- A eration;the'parts in vnormal positions. Fig. 24 is a view similar to Figy23,ybut showing a linkage as having been op erated't'o restoreia'previously'IT 'set 9 pin.V

It'will be understoodtliatbefore the operation. O14 Said linkage, thepari; depressed thereby occupied the position shown in dot-v ted lines.Y l 'i l FigfQ is a sectional side elevation of a portion of thebichrome ribbon mechanism offan Underwood typewriter. 'A

Fig. 26 isa side velevationy of a portion of a pin-carryingwheel-operating rack bar, illustrating'the setting of onev pin at thesubtraction operation, vand the simultaneous res-V toration of' thepreviouslyY set"9 pin, as atifigjee.

'Figf 27 is a sectional elevation from front to rear Vof the parts attheleft-hand portion of the 'computing machine, showing them in normalpositions.` l 'l v Fig. 28 is a Vsectional elevation of the parts attheA oppositev side of the machine base, in normal positions. 'i

` Fig. '29 `is` an elevation of the principal portion of the mechanismfor resetting the wheels to zero.

' Fig. 30 is a sectional elevation'otthe ist mechanism for correctingerrors, that is, for restoring to normal positions the set pins, thesubtraction devices, etc.

Fig. 31 is a perspective rear view of the Underwood bichroine ribbonmechanism and its connections to the subtracting mechanism of themachine.

Fig. 32 is a plan of the jacks and certain other portions of thewheel-selecting mechanism vconnected to the typewriter carriage.

Fig. 33 is a rear elevation of the jacks and the links which connectthem to other portions of the wheel-'selecting mechanism at the bottomof the machine.

Fi 34C is a elan et of number wheels and a tens-carrying train.

Fig. 35 is a sectional side elevation of the same. Y

Fig. 36 is a view similar to Fig. 35, but illustrating the method ofoperation of the tens-carrying train.

Fig. 37 is a perspective view of an arbor on which are mounted thecomputing wheels, showing particularly part of the means whereby thewheels are returned to Zero.

Fig. 33 is a sectional side elevation of Va portion of the mechanism forreturning the wheels to zero.

Fig. 39 is a side elevation on a larger scale of one of the numberwheels and its appurtenances.

Fig. 40 is a sectional view of the same.

In the Underwood-Hanson combined typewriting and adding machine,illustrated in the drawings. alphabet keys 1 and numeral keys 2 (Fig. 2)operate to depress levers 3, to vibrate bell cranks 1 to swing type bars5 upwardly and rearwardly against a platen 6. The platen shifts topermit different types to print, being mounted in a vertically shiftableplaten-frame 7 having a roll 3 to run on a shift-rail 9. rlhe platenframe is connected by arms 10 to a non-shifting letter-feeding carriage11; said arms mounted on a rock shaft 12, which is journaled in saidcarriage, permitting 'the platen frame 7 to shift-up and down. Saidcarriage 11 has a rack 12a, meshing with a pinion 13 forming part of aletter-feeding mechanism. The carriage is driven by a spring barrel 1&1and strap 15, Fig. 3. Each type bar has a heel 16 to koperate auniversal bar 17, which controls dogs 18 to cooperate with an escapementwheel 19 connected to said pinion 13, so that as every type key isoperated, the carriage 11 is fed a letter-space.

Referring to Figs. 1. 2. 3, 32 and 33, on rock shaft 12 are rigidlymounted two wardly extending arms supporting a rod on which is rotatablymounted denomination selecting tappets 20. adjustable along said rod,and capable of being locked in any desired position bymeans of a tooth22 engaging one of a series of notches 23Y formed in a, rack bar 24.,also carried by said armsY Each tappet 20 has a tooth 25 to engageconsecutively with jacks 26 and lift the latter; the tooth being beveledor cam-shaped for this purpose, and the jacks being correspondinglyshaped. The jacks are levers pivoted upon a rod 27 fixed on theframework; and, when actuated by tooth 25, each jack depresses one of aseries of thrust rods 23, Figs. 2, 3, 5, 7. These jacks and thrustrodsare employed for the purpose of selecting the computing wheels to beoperated, or of determining the denomination of the number which is tobe added, or in other words, of determining the place in a column inwhich computing is to be eected. The irst jack to be operated by thetappet 20, as the carriage runs in letter-feeding direction, is the jackof highest denomination, for instance millions.

The connection from the j acks to the computing wheels is as follows:The rods 28 at their lower ends are pivoted at 29 to levers 30. (Figs.5, 7, 8, 18, 19) the latter pivoted loosely between their ends upon afixed rod 31, and extending forwardly therefrom beneath a set of links32, overlying which are forwardly eXtending denominational orcolumn-selecting rack bars 33 for operating the computing wheels 34 atthe front of the machine. Said links 32 have pendent stems 35 to beengaged and lifted by the forward ends of the levers 30, and also risingstems 36 to engage and lift the wheel-operating rack bars 33. Fach ofsaid links 32 forms a member of a linkage; the other members of whichcomprise diagonal links 37 and a connecting link 38; wherebj.1 each link32 is caused to rise about vertically. These linkages serve to formcrossoonnections between the jacks 26 and the rack bars 33; thedenominational order ot' the latter being the reverse of that of theformer; the jack 26 of highest denomination at Fig. 1 being at the rightof the series` while the computing wheel 34 of highestde-l nomination isat the left of the series.

Each of the rack bars 33 carries at its forward end teeth 39 to meshwith a pinion 4() with which each of the computing wheels 3e isprovided, Figs. 5. 35 and 39.

The effect that each jack 26 has on its associated rack bar 33 is tolift the rear end of the latter, while the other rack bars remain innormal positions; and the purpose of lifting or selecting the rack baris to permit the setting of any selected one of a forwardly extendingrow of pins 41 thereon; the pins being set by means of said numeral keys2.

Said numeral keys are connected respectirely to transverse pin-settingbars -12 overlying the pins 41, but incapable of reaching the latterwhen the rack bars 33 are down in normal positions; but if any rack baris lifted by its jack 26, the manner al ready explained, then thedepression of any `numeral key 2 (the carriage 11 remaining stationary)will causeV the corresponding setting-bar 42 V,to descend and engage theunderlying pin 41, to force the latter to project down below the loweredge of its rack barV 33. This downwardly-projecting pin then serves asa lug, by which the rack bar is driven forwardly to rotate itsassociated computing wheel in a manner that will presently be explained.y

When the carriage 11 is moved to such a position that a tappet 20 is inthe field of the jacks 26, and one of the latter is lifted by thetappet, if a key 2 be depressed, it will push down a steml 43, (Figs. 7,17, 21) to operate a linkage, whereof said pin-setting bar 42constitutes a member. There are nine pins 41 (marked 1 to 9 on each rack33, forming a row extending longitudinally of said rack bar; and thepins on all the rack-bars taken together form rows extending crosswiseof the machine, a'b ar-42 overlying each row. Each bar 42, as seen bestat Fig. 21, forms a link between opposite bell-cranks 44; beingconnected to horizontal arms of said bell cranks; the vertical arms 44aof said bell cranks are connected by horizontal links 45; these links 45having wrists 46, engaged by slotted arms 47 xed uponforwardly-extending rock shafts 48, carrying horizontal rock arms 49just beneath and in position to be engaged by the descending key stems43, Figs. 2O` and 21. The manner in which each of the pinsetting bars 42overlies a transverse row of settable pins 41 is clearly illustrated atFigs. 5, 7 and 2l. The linkages 42, 44 and i 45 are marked 1 to 9 andform a nest is operated by the numeral key 2, the nextl by the numeralkey 3, and so on; there being nine of the linkages. The forward pinvsetting bar 42 being, as just explained, operatedby the numeral key 1,is capable of depressing the foremost pin 41 on any of said rack bars33. This pin is situated so far forward on said rack bar, that only aminimum stroke is given to the latter by a subsequent operation of themachine; and hence the associatedv computing wheel 34 is turned aminimum distance, that is, onetenth of a revolution.

The device that carries the rack bars forward is a horizontal bar50,-which is caused to move horizontally forward and pick up the rackbars 33 by means of the projected pins 41, so that the strokes of theseveralV rack bars, and hence of their associated computing wheels,depend upon which pin in each rack bar was depressed, or in other wordswhich numeral key was operated.'

The tappet 2O on the carriage selects the wheel, and any numeral key 2may determine the extent of rotation of theselected wheel. Upon thereturn of key 2, the carriage 11 feeds, randthe tappet 20 lifts the nextlower jack 26.

Said horizontal bar 50 forms a part of a general operator, which alsocomprises a pair of slides 51, 51a, at opposite sides of the machine,(Figs. 19, 27, 28)'mounted in suitable guides or tracks upon the baseand rigidly connected by said'bar 50, as well as by a forwardcross-bar52 vjust beneath the rack bars 33; the slides and the bar taken t0-gether forming a movable frame or carriage, and constituting the generaloperator of the computing wheels. These 'slides are formed with racks53, to mesh with pinions 54 pivoted upon the side walls of the machineframe, said pinions in turn meshing with segments 55 fixed upon theopposite ends of a horizontal rock shaft 56 extending across the machineand carrying at itsright hand endoutside of the frame a long handle 57,which is swung forwardly from the Fig. 28 position to advance thegeneral operator and cause the bar 50 to advance the rack bars 33, 'toturn the pinions 40 and computing wheels 34. Upon the return stroke ofthe handle 57 said cross bar 52 of the general operator engagesshoulders 58 (Figs. 5, 7, 15', 30) formed upon the under sides of therack bars 33 and returns them to normall rear positions.

During the last partl of the return stroke of the general operator, auniversal pinrestorer in the form of a horizontal plate or tablet 59(Figsj, 7, 8, `9, 2 1) is caused to lift and restore all of thedepressed pins 41 to their Vnormal positionsv on the rack bars 33 (thisbeing a function of said general operator). Said universal restoringplate is actuated by a cam`60 (Fig. 7 mounted upon the left hand slide51 of the general operator to engage a rock arm 61 pendent from ahorizontal rock-shaft 62, the latter extending across the machine andmounted in the side walls of the machine frame, and

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having near its middle an arm 63 toengage andlift a projection 64.provided on said universal pin-restoringV plate 59. The latter ismounted for up and down parallel movement by means of forward and rearears 65, which are pivotedv to horizontal arms of bell cranks 66, 67,the former loosely mounted on said shaft 62 and the latter looselymounted on a shaft 68 parallel with said shaft 62. Said bell crankscomprise pendent arms 69 which are connected by a link or links 70. Atthe last part ofthe return stroke of the general operator, the cam 6()engages the arm 61 and turns the shaft 62, causing arm 63 .thereon torise and lift said pin-restoring plate. It will be'inoticed` slide 51,to permit it to pass freely under the arm 61 during the forward strokeof the general operator.

When the racks are being returned rearwardly by bar 52 of the generaloperator, the pinions 40 turn idly, the latter having pawl devices 7 0-to engage with ratchet wheels 71 (Fig. 39) fixed inside of the computingWheels 34, which rotate always in the same direction.

The computing wheels are held steady by spring detents 72, Fig. 5, whichengage gears 73 fixed on the respective computing wheels; said gears 73serving also as tenscarrying gears. The tens-carrying operation isinitiated by special teeth 74 (Figs. 4, 35, 36, 39), one of which isfixed upon each of the computing wheels 34, in position to engage andoperate once in each-revolution of wheel 34 an adjacent tens-carryingpinion 75, the latter provided with a three-toothed gear 76 in positionto mesh with and turn 'the gear 73 fixed on the computing wheel 34 ofnext higher denomination. Although the tens-carrying operation dependsupon the actuation` of a pinion 75 by the tooth 74 upon the computingwheel 34, still such tooth merely initiates the tens-carrying operation,the latter being completed by means otI one of a. series of power-drivenrocking segments 77 There is one segment 77 for each of the computingwheels except the units wheel; and these segments are fixed upon aftransverse horizontal shaft 78 which has at one end a pinion 79 (Figs.5, 13, 27), the latter meshing with an idle pinion 80, which in turnmeshes with the teeth 53 on 4[he left-hand slide 51 of the generaloperator, so that the pinion 79 is rotated forwardly and backwardlyabout a complete revolution at each cycle of movements of said generaloperator. The tens-carrying segments, however, are intended to rotateonly in one direction; and hence the shaft 78 on which they are fixed isconnected by a ball or other clutch 81 with said pinion 79, so that therotation of the pinion during the advance of the operatorie an idle one;the segment shaft 78 being turned only during the return stroke of theoperator. In other words, during the forward stroke of the generaloperator, the teeth 74 on certain of the computing wheels 34 operate toset the tens-carrying pinions 75, and during the back stroke of theoperator, the segments 77 engage the pinions 75 and complete thetenscarrying operations by giving one-tenth of a revolution each to thecorresponding computing wheels 34. The tooth 74 on each wheel 34 impartsto the tens-carrying pinion 7 one-ninth of a revolution; there beingnine teeth on said pinion; and each segment 77 is intended to turn itspinion two-ninths of a revolution; each pinion being thus turnedone-third of a revolution in all, in

order to rotate the gear 73 and the next wheel 34 one-tenth of a.revolution.

Every third vtooth on each tens-carrying pinion 75 is cut away, aportion 82 being left, however, sufficient to be engaged by a springdetent 83; the tooth being cut away so that the tens-carrying segments77 may swing idly past the tens-carrying pinions when the latter areidle; the gap between the teeth adjacent t0 the cut-away tooth beingsufficient to permit the free movement of segment 77. The tooth 74 onany computing wheel 34, by moving the tens-carrying pinion 75 one-ninthof a revolution, turns said pinion into position for engagement by itsassociated segment 77 upon the next return movement of the generaloperator; whereby said pinion is advanced an additional two-ninths, andthe wheel 34 of next higher denomination is turned onetenth of arevolution. The segments 77 are arranged in spiral order on the shaft78, so that tens carrying may proceed from low to high denominationsthroughout the gang of computing wheels during a. single return strokeof the general operator, whereby all the wheels may be turned from 9 to0 progressively during said operator stroke.

In order to return the computing wheels to zero, a key 85 is depressed,Figs. 1, 29, and its stem depresses the front end of a lever 86, therear end whereof is provided with a. wrist 87, which takes under andlifts the rear end of a special rack bar 88, which is similar to therack bars 33, but is provided with only one settable pin 88a similar topins 41. Said pin 88a encounters a fixed abutment 88h, and hence stopsbefore the upward movement of the rack bar 88 is completed, or in otherwords, the pin is forced to project below the rack bar by the upwardmovement of the latter. Upon then pulling forward the handle 57, thecross bar 50 of the general operator is moved to engage said projectingpin 88a and carry forward the special zero rack bar 88, the forward endof which has teeth to mesh with a pinion 89, which has a ball-clutchconnection to a disk 90, the latter being fixed to an arbor 91 uponwhich all of the computinwheels 34 are loosely mounted, Figs. 35, 3f and38. This arbor, which is given a full revolution by the general operatorat the forward stroke of the handle 57, (since pin 88 is placed one stepto the rear of 97 pins 41) has a clutch connection with every one of thecomputing wheels 34, so as to bring the units wheel to zero point, andthe remaining wheels to such positions that they all show 9 at the sightopening. The arbor 91 turns a full revolution; but all except the unitsclutch are set to such positions as to be capable of giving theircomputing wheels each only nine-tenths of a revolution. The units wheel34, in thus being

